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Recent content by JohnRwals

  1. JohnRwals

    Precast Parking Structure: Double Tee Production & Bearing Connection

    This is a kind of improved design method or sophistication of existing knowledge. Currently bearing pad design issue is not cleared completely yet. I guess ROF is more popular than plain elastomer bearing in the parking structure double tees.
  2. JohnRwals

    Precast Parking Structure: Double Tee Production & Bearing Connection

    Here is my personal solution/suggestion. I am looking forward your comments. 1. All these double tee bearing connection movements are dynamic due to vehicular impact load, thermal change, member cambers, etc. 2. Providing uniform loading conditions is expensive and hardly practical. 3...
  3. JohnRwals

    Precast Parking Structure: Double Tee Production & Bearing Connection

    Typical double tee bearing plate size is 4"(W)x8"(L). Maximum 1/8" plate tilting tolerance is applicable according to PCI standard/manuals.
  4. JohnRwals

    Precast Parking Structure: Double Tee Production & Bearing Connection

    Sloped bearing corbels in the litewall and sloped ledge in the spandrel? Are those special treatments worthy effort? Economy and production efficiency due to non-rectangular forms should be considered. I understand similar issue could be critical in the bridge industry with heavier loads. What...
  5. JohnRwals

    Precast Parking Structure: Double Tee Production & Bearing Connection

    Hello! These questions are related with precast production efficiency and member design detail. Double tee floors are sloped everywhere in the precast concrete parking structures; let's assume 60ft long 12DT34 and typical floor slope 2% for drainage. 1. Is it really necessary to make double...
  6. JohnRwals

    Precast TT slabs welding of stems to girder corbels

    Joe, But, as DTs can move due to temperature change or applied dynamic loadings, this rigid restrained welding connection could cause failure around the connection rather than improved stability.
  7. JohnRwals

    Precast TT slabs welding of stems to girder corbels

    Generally, double tee and girder welding connection is not recommended.
  8. JohnRwals

    Concrete Wall Surface Finish (food processing facilities)

    Hello! Food processing facilities require special finish on concrete wall surfaces. Where can I obtain detailed information with respect to this issue? FDA? _JRW
  9. JohnRwals

    Prestressed Concrete Insulation Wall Design

    The following info came from PCI committee's report, which I have edited as an example. Insulation walls can be used for both load bearing and non-load bearing walls. Composite action with shear connectors may allow this system applicable to high ceiling structures. I guess similar problems...
  10. JohnRwals

    Prestressed Concrete Insulation Wall Design

    Aesur, I understand your questions and concerns. I think this area is really tiny niche market, but growing industry. PCI's committee report "State of the Art of Precast/Prestressed Concrete Sandwich Wall Panels, 2ned Ed." will provide general knowledge. -JRW
  11. JohnRwals

    Prestressed Concrete Insulation Wall Design

    Hello! I am looking at 8" think precast prestressed concrete insulation wall design ONLY with strands and shear connectors. (No WWR or additional reinforcement except solid zone around stripping/handling anchors.) As strand layout was decided for the wide pieces with opening in the middle of...
  12. JohnRwals

    Corrosion Prevention with Patching

    Hi! I wonder this patch method with cement grout can be used to prevent corrosion issue in the food processing facilities. I saw this method in the precast concrete projects. Is it acceptable detail to avoid corrosion-related problems with black finish plates and angles? Thanks! _JRW
  13. JohnRwals

    Pretensioned Beam Deformation

    Hello! In order to check connection details during erection stage in the precast concrete beams, I am looking for a book or papers explaining how to predict section behaviors after prestressing force is applied. I am interested in horizontal deformation rather than vertical deflections/cambers...
  14. JohnRwals

    Adjusting top of deck elevations on a pre-topped twin tee

    Generally, 2% double tee slope is adopted due to floor drainage. On top of 2% drain slope, there should be 2"~3" camber due to pretensioning. So, it is hardly possible to satisfy 2% ADA floor slope requirement with pre-topped double tees. Should these double tees be field-topped, so topping...
  15. JohnRwals

    Barrier Cables in the Parking Structure

    Of course, intermediate posts should be added as required. (That topic is beyond this discussion.) Generally, vehicle impact and pedestrian fall protection should be considered simultaneously.

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